Changes in Wall Mechanics After Endovascular Stenting in the Rabbit Aorta

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Abstract
OBJECTIVE. The aim of this study was to evaluate changes in the wall mechanics of small-diameter arteries after endovascular placement of three different stents. SUBJECTS AND METHODS. Five self-expandable stents (Wallstent), five balloon-expandable noncovered Palmaz stents, and three balloon-expandable covered stents (Jostent) were placed in the infrarenal aorta of 13 New Zealand white rabbits. Systolic blood pressure changes, blood-flow velocity, systolic diameter, and diameter changes were measured and used to calculate the diameter compliance, the distensibility coefficient, and the pulsatility index. RESULTS. Compliance (10-3 mm kPa-1) was 75.3 ± 20.1 before stenting and reached 94.7 ± 42.2 upstream, 38.8 ± 14.2 at the stent level (p < 0.05), and 70.8 ± 23.2 downstream from the stent. Distensibility (10-3 kPa-1) was 24.3 ± 6.3 before stenting and reached 27.8 ± 10.3 upstream, 10.5 ± 4.4 at the stent level (p < 0.001), and 21.9 ± 8.6 downstream from the stent. Compliance and distensibility were significantly lower at the stent level than upstream and downstream (p < 0.05). Aortic diameter increased significantly at the stent level from 3.11 ± 0.40 mm before to 3.76 ± 0.42 mm after stenting. No significant difference was found among the three stent designs for all the studied data. CONCLUSION. Regardless of the three tested stent designs, endovascular stenting produces a significant decrease in arterial wall compliance of the rabbit aorta.